Intramolecular [3+2]-cycloaddition of salicylaldehydes-based cyclic azomethine imines to access novel tetrahydrochromeno[4,3-c]pyrazolo[1,2-a]pyrazol-9-ones

Abstract An efficient intramolecular [3 + 2]-cycloaddition of in situ-formed salicylaldehyde-based N,N′-cyclic azomethine imines was successfully developed to access novel tetracyclic skeleton bearing three contiguous stereogenic centres. This established protocol features high functional-group tolerance, excellent chemical yields, good diastereoselectivities, and variable reaction conditions.